Sources that are part of the Source trait should not have public factories.

[dvdsk]

Clarifying example: source_instance.speed(1.5) wraps whatever source instance its called on in a Speed struct (which is itself again a Source). The Speed struct can also be constructed by using speed::speed::new(source_instance, 1.5)

The latter is clearly not meant to be used as the docs for such factories are often along the line of:

rodio/src/source/speed.rs

Line 7 in 95a466e

/// Internal function that builds a `Speed` object.

This specific example was made before pub(crate) existed (yeah rodio is 9 years old and still improving 🥳 ) see: https://releases.rs/docs/1.30.0/.

I propose that a source's factories are made private to the crate (pub(crate)) when the Source wraps an inner source.

This:

• steers users in how to use Rodio
• reduces the API surface, easing maintenance
• removes the need for documentation

When implementing care should be taken to copy/merge the documentation to/with that on Source::.